July 14 - Tyson Gay and Asafa Powell, two of the world's leading sprinters in recent years, are both facing doping suspensions after reports of positive tests.
Gay, the former world 100 and 200 metres champion from the United States, was expected to mount a huge challenge to the double Olympic champion Usain Bolt of Jamaica at next month's International Association of Athletics Federations (IAAF) World Championships in Moscow, but has admitted testing positive for a banned substance.
Powell, the former 100m record holder, was one of five Jamaican athletes reported to have tested positive for banned substances.
Powell and Sherone Simpson are three of the five, according to reports.
The Jamaica Gleaner reported that five Jamaicans had tested positive and confirmed Powell and Simpson.
Powell, 30, held the world record in the 100m of 9.74 seconds until Bolt reduced the mark to 9.72sec shortly before the Beijing 2008 Olympics.
Powell is the fourth fastest man of all time, behind Bolt, Gay and compatriot Yohan Blake.
He failed to make the Jamaican team for the forthcoming World Championships, finishing seventh in the 100m at trials.
Simpson, 28, was the 2008 Olympic silver medallist in the women's 100m.
"I don't have a sabotage story," a tearful Gay told Associated Press in a phone interview from Amsterdam.
"I basically put my trust in someone and was let down."
Gay fought back sobs in the interview, according to the AP.
He would not reveal the substance that led to the positive test.
He says he was notified by the United States Anti-Doping Agency (USADA) on Friday (July 12) that a sample came back positive from an out-of-competition test on May 16.
He says he will have his "B" sample tested soon.
"It is not the news anyone wanted to hear, at any time, about any athlete," USA Track and Field chief executive Max Siegel said in a statement.
Gay claims full responsibility and insists he will reveal "everything".
"I have to go over everything with USADA first," Gay told the AP.
"I will take whatever punishment I get like a man.
"I do realise and respect what I put in my body and it is my responsibility.
"I'm going to be honest with USADA, about everything, everybody I've been with, every supplement I've ever taken, every company I've ever dealt with, everything."
Gay, 30, has overcome a series of injuries over the past few years but has been in great form this season, recording the three fastest 100m times of the year, the best of them 9.75sec, and the fastest 200m of the year with 19.74sec before Bolt trimmed 0.01 off it at the Paris Diamond League meeting.